While you may feel guilty, most crushes are totally normal. Here's how to know when you're crossing the "loyalty line" into cheating territory.

If you pinch your cheeks when the cute UPS guy arrives, your secret is safe with us — and you don't need to feel guilty. "Being attracted to other people after you're taken is normal," says Andrea Syrtash, an advice columnist and author of the new book Cheat on Your Husband (With Your Husband). "Women assume it means something is wrong at home, but I'm happily married and I've had crushes on everyone from the guy who checks me out at the grocery store to coworkers. It's fleeting and fun. We're social animals and need to connect with people." In fact, if you bring home the rush you get from flirty exchanges, your connection with your partner can actually benefit from it. "When you have a crush, it reminds you that you're a sensual, sexy woman, and every one of us needs that," she says. "It can inspire you to channel that energy into your own marriage and flirt with your husband as well." All that said, if a crush turns truly lustful or consumes your thoughts, it's time to back off. "It's normal to fantasize, but you'll know you're crossing the loyalty line if you start to conceal your interactions with your crush," says Syrtash. That may be a signal that your relationship at home needs some special attention.